ASTM International

Standard Guide for Characterization and Use of Hygrothermal Models for Moisture Control Design in Building Envelopes
 N E3054/E3054M

Annotation

This guide offers guidance for the characterization and use of hygrothermal models for moisture control design of building envelopes. In this context, “hygrothermal models” refers to the application of a mathematical model to the solution of a specific heat and moisture flow performance issue or problem. Hygrothermal models are used to predict and evaluate design considerations for the short-term and long-term thermal and moisture performance of building envelopes.

Each hygrothermal model has specific capabilities and limitations. Determining the most appropriate hygrothermal model for a particular application requires a thorough analysis of the problem at hand, understanding the required transport processes involved, and available resources to conduct the analysis. Users of this guide can describe the functionality of the hygrothermal model used in an analysis in a consistent manner.

This guide applies to hygrothermal models that range from complex research tools to simple design tools. This guide provides a protocol for matching the analysis needs and the capabilities of candidate models.

This guide applies to the use of models that include all or part of the following thermal and moisture storage and transport phenomena: (1) heat storage of dry and wet building materials, (2) heat transport by moisture-dependant thermal conduction, (3) phase change phenomena (for example, evaporation and condensation), (4) heat transport by air convection, (5) moisture retention by vapor adsorption and capillary forces, (6) moisture transport by vapor diffusion (molecular and effusion), (7) moisture transport by liquid transport (surface diffusion and capillary flow), and (8) moisture (vapor) transport by air convection.

This guide does not apply to cases requiring analysis of the following: (1) convection that occurs in a threedimensional manner or through holes and cracks; (2) hydraulic, osmotic, or electrophoretic forces; (3) salt or other solute transport; or (4) material properties that change with age.